Paper manufacture



June 21, 1938. R. GROWDON PAPER MANUFACTURE Filed May 1, 1934 2 Sheets-Sheet l attorney June 21, 1938. GROWDQN 2,121,540

PAPER MANUFACTURE Filed May 1, 1934 2 Sheets-Sheet 2 Zhwentor Maxi/6L f (Ittorneg tion operation on its lower or wire side.

Patented June 21, 1938 UNITED STATES PATENT OFFICE PAPER MANUFACTURE Application May 1, 1934, Serial No. 723 ,362

Claims.

This invention relates to the manufacture of paper and more particularly to paper manufacture in which fibrous stock is flowed onto a forming wire to effect an initial definite web formation, after which additional paper forming material is-added to the wire side of the web to be incorporated as part of the subsequently finished sheet.

One of the principal objects of the invention is to provide a method of incorporating and properly distributing additional paper forming material in a web of paper before its formation into a dried sheet of paper is completed.

It is a further object to provide a simple construction of apparatus for carrying out the invention. v

It is also an object to provide as a new article of manufacture a sheet of paper so made and comprising a fibrous material and filler in which the filler is distributed upon both sides of the paper sheet in controlled manner, the surface of the sheet of paper being free of suction roll marking.

Other objects and advantages will be apparent from the following description, the accompanying drawings, and the appended claims.

In the drawings,--- 7 Fig. 1 is a diagrammatic view showing one manner of practicing the present invention;

Fig. 2 is a detail view showing a slightly modified construction for carrying out the invention;

Fig. 3 is an alternative arrangement of apparatus suitable for carrying out the invention; and

Figs. 4 to 6 are detail views showing further modifications of apparatus for performing the invention.

In accordance with the present invention, paper making stock is fiowed onto the traveling wire of a forming machine through which drainage is efiected in the usual manner to effect an initial definite web formation. A suction couch roll is preferably provided so that as the web passes over the couch roll, it is subjected to a suc- This suction operation, in addition to the drainage action taking placealong the forming wire and the usual suction boxes, causes the removal of water and certain portions of the paper stock such as the finer fibers and part of the filler material if such is present in the stock, particularly from the wire side of the web. The removed water and other material, commonly referred to as white water, is collected andrecirculated to be reused, thereby preventing the loss of any of the paper forming constituents which have passed through the wire.

Thereafter the web is removed from the forming wire, and suitable apparatusis provided for applying additional paper forming material to the 5 wire side of the web before its formation into a dried paper sheet is completed. This additive material may be supplied in suitable amount to provide predetermined surface characteristics in the finished sheet either by way of compensation for that-material which was removed from the wire by drainage, or as new material supplied to impart desired characteristics to the web originally formed either with or without filler.

Thereafter the web, with its additional paper forming material, and while still wet and in a sufficiently receptive condition, is subjected to a suction operation, the suction being applied to the side of the sheet opposite that to which the additional paper forming material was added. This results in incorporating the additional paper forming material in a very satisfactory manner into the body of the sheet, and prevents withdrawal of a large part of the additional material in the suction operation such as occurs when suction is applied to the same side of the sheet as that to which the additional material has been added.

Inasmuch as the additional paper forming material is not added until after the web has left the forming wire, the web is in a relatively drier state than it is prior to its passage over the couch roll. Accordingly a larger quantity of additional paper forming material can be incorporated and maintained upon and within the body of the web than when such additional material is added to the web while still on the wire, and likewise a better control is obtained over the way in which it is added. Similarly, because of a drier condition of the sheet, there is practically no marking effect such as may be produced by high vacuum suction rolls. To further eliminate the undesirable effect of suction roll marking, the sheet is preferably subjected to suction while supported upon a felt. In this way, with the suction being so applied through the felt, the objectionable effect of marking in the pattern in the perforations of the suction roll is entirely eliminated for the very fine interstices of the felt so distribute the suction action as to prevent any such marking.

The construction further has the added advantage that the system for the application of the additional paper forming material is entirely separate from the white water system of the forming machine. As is well known, the common practice in the manufacture of paper is to collect the drainage water draining through the forming wire and to recirculate it back to the stopk chest for reuse. This drained water, commonly known as white water, contains a considerable quantity of the smaller fibers and entrained mineral materials which have passed through the wire, and accordingly it is important that this material be recovered and reused. Also upon the breaking of the sheet, and its failure to pass over to the presses and the driers, the entire web is carried around by the wire and is washed off into the same collecting means by means of showers. Under such temporary circumstances it is customary to keep the machine operating, all of the web material being collected and continually recirculated, but the supply of new stock constituents is cut off to prevent the accumulation of such material in the recirculating system. If then no additional paper forming material is added, the entire web material is recirculated during the period of the break, without any change in the proportions thereof for no material is added or lost in any appreciable quantities.

When however, additional paper forming material is added, as for instance by means of the wire guide roll, such addition takes place continually and this additional material is recirculated in the white water system and results in a continual building up of the proportion of the additive material since more is being continually added and none lost. Accordingly when the web again carries through, it will have an abnormally high percentage of the additive material and the result will be the production, for a period of time, of paper of non-uniform characteristics. This produces an undesirable operating condition, resulting in loss of a part of the formed paper, and makes it difiicult to obtain accurate control of the constituents of the sheet.

The present invention is so carried out that the white water system is entirely separate from that including the additional paper forming material. The arrangement is such that the additional paper forming material is supplied only in case a web is being removed from the forming wire, and is so supplied to the web that in any event no drainage takes place into the white water system. Thereby it is possible to maintain accurately controlled and predetermined stock constituents.

Referring to the drawings which illustrate a preferred embodiment of the invention, paper making stock from a head box (not shown) is supplied to a traveling forming wire in with resultant initial formation of a web of paper l2. The wire passes over the couch roll [3 which is provided with the conventional suction box construction I4. The remainder of the forming machine construction and the white water collecting system is not shown as it may comprise a conventional arrangement of such.

In the arrangement shown in Fig. 1, the web, after leaving the couch roll, passes under a guide roll i5, and is then carried forwardly upon an auxiliary traveling wire 16 which rotates around a plurality of guide and driving rolls l1. arrangement comprises an application roll [8 rotating in a bath of the additional paper forming material. The constituents of this material may be chosen at will to provide predetermined characteristics, but generally it will consist principally of a mineral filler material in conjunction with a size. Conventional mechanism may also be provided for maintaining a predetermined This.

level of the material in the trough i8. For example the material may comprise a suspension of a carbonate, or other similarly acting filler in water, containing 22 pounds of carbonate filler and 3.5 pounds of size, such as boiled starch, in 40 gallons of water.

Roll l8 carries a film of this material upwardly into contact with the traveling wire l3, and the additional paper forming material is thereby carried into contact with and incorporated within the body of the paper web l2. Part of the water has been removed before the web reaches this point and it is in a receptive condition for such additional material.

After the additional material has been added to the web, the web is brought into contact with a traveling felt 20, traveling in the same direction as the paper, which is directed into contact with the upper surface of the web by a guide roll 2|. This felt couches the web from the auxiliary wire and carries it upwardly around a second guide roll 22. From the guide roll 22 the web is carried into a suction press, indicated generally at 23, the felt continuing through the press and around suitable tensioning mechanism 24 which is adjustable in the usual manner.

The wet press 23 comprises an upper roll 25 and a lower roll 26 which latter is provided with a suction box arrangement 21. The purpose of this arrangement is to apply suction to the side of the wet web opposite that to which the additional.

paper forming material was added, to remove water from the web, and at the same time to compact the constituents of the sheet by drawing the newly applied material into the web interstices and distributing it therein. The preferred manner of so doing is to turn the web over by the arrangement just described and then to apply suction to the lower side thereof, which is the side opposite that to which the additional paper forming material was applied.

It will be noted that as the web passes through the first press 23, it is supported by the traveling felt 20. Furthermore the suction is effective upon the web through the felt 20. Consequently no suction roll marking will be obtained. Inasmuch as any marking produced by the suction couch roll has been eliminated by the application of the additional paper forming material to that side of the web, the result is to provide a web of very superior surface characteristics on both sides, and substantially completely free of any suction roll marking.

It should be further noted that in this embodiment, the felt contacts the side of the web opposite that to which the additional paper forming material was added. Suction is applied through the web but the surface of the web at the time the suction is applied is in a sumciently definite stage of formation so that the suction effect on the newly applied material tending to draw it down into the web results in only incidental material being drawn from the formed web into the felt. Thus no objectionable effects are imparted to the surface of the sheet and no objectionable loading of the felt with filler or the like occurs. Consequently the felt life is prolonged and dim. culties in cleaning the felt are not encountered.

After leaving the first press 23, the web passes over suitable guide roll 30 and is then carried forward upon a traveling felt 3| and through the rolls 32, 33 of a second wet press. This press performs the usual wet pressing operation. If desired the sheet may be carried on a felt 34 through a third set of press rolls 35, 36 after which it passes to thedriers, indicated generally at 31 where it may be dried in the conventional manner. 1

Fig. 2 shows a slightly modified arrangement comprising the traveling wire I8, and a color application roll I8 operating in a trough I9. Instead however, of couching the web I2 from the auxiliary wire by means of a traveling felt, the felt 28 is carried around guide rolls 2|, 22' without contacting the web. The web passes around auxiliary guide rolls Ma and 22a supporting itself, and is thereafter carried through the press 23' comprising rolls 25, 26' and suction device 21', upon the felt 28. In cases where the web is not sufliciently strong to be self sup porting, this arrangement will not be satisfactory, and the arrangement of Fig. l in.which the web is actually carried upon the traveling felt will give better operating results.

Fig. 3 shows a modified arrangement in which 'the web, though still wet, contains less moisture at the time of the application of the additional paper forming material thereto. In this arrangement the web is first subject to a preliminary pressing operation before the additional paper forming material is added. Referring to Fig. 3, the wet web is shown at '40, upon the traveling forming wire 4|. The couch roll 42 is provided with a suction box 43. Upon leaving the couch roll, the web passes under guide roll 44 and is carried forward upon a traveling felt 45. The felt carries the web through a set of press rolls 46, 41 the latter of which may be provided with a suction box '48 to further reduce the water content of the sheet. A suitable mechanism 49 provides for the driving and tensioning of the endless felt 45.

After leaving the press rolls 46, 41, the still wet web passes over a guide roll 59 and is then supported upon an auxiliary member 5|, preferably a wire. A suction box 52 may be provided for drawing the web down into close contact with the wire. Thereafter the wire passes over an application roll 53, rotating in a trough 54, which is supplied with the additional paper forming'material. This roll operates as described above to supply a'predetermined amount of the additional paper forming material to the web through the auxiliary forming wire. Thus any marking produced by suction rolls 43 or 48 is obliterated. The wire passes over a guide and driving roll 55, which may conveniently be the bottom roll of the conventional second press.

The web with the additional paper forming material supplied to the wire side thereof next passes to an auxiliary traveling felt 58 which carries the web toward a wet press indicated generally at 69. The web leaves felt 58 and is turned around guide rolls 6|, 82 which turn it over and guide it toward the nip of the press. A traveling felt 53 travels over suitable guide rolls 64 and is arranged to support the web and carry it through the press 69. If the web does not have sufllcient strength to be self-supporting, the felt may be used to couch the web from the wire, in the manner shown in Fig. 1. g

The lower roll 65 of press 69 is provided with a suction box 86. As in the other arrangements, this provides for the application of suction from the bottom side of the web, which is the side opposite that to which the additional paper forming material was added. As described above, the 'eifct of suction on this side of the web is to provide for the incorporation and distribution of the additional paper forming material into the body of the web.

After passing through the third press 80, the web passes to suitable driers 81 where it is dried in the conventional manner.

In; Fig. 4 there is shown an alternative arrangement of means for applying the additional paper forming material to the web. In this modified construction the wet web 19, after leaving the couch roll of the forming machine, is brought into contact with and is carried forward by a member 1| which may comprise a traveling felt or the like. If desired the web may also be subject to a wet pressing operation after leaving the couch roll. The web is then carried around guide rolls 12, 13 which are so positioned that the web travels substantially vertically upward. A traveling felt 14 is carried over guide rolls 15. I6, and 11. The guide roll 18 is so positioned that it brings the felt against the web 18 intermediate rolls 12 and 13 to thereby support the web. An auxiliary wire 18 is arranged over guide rolls 18, so that it travels substantially parallel with the travel of the web 19 but spaced slightly therefrom. The wire passes over a fountain roll 8| rotating in a trough 82 to which the additional paper forming material is supplied. Preferably the parts are constructed to cause the travel of the auxiliary wire in the direction indicated by the arrow, opposite to that of the travel of the wire where the web and the wire are adjacent each other. In passing over the fountain roll 8|, the wire picks up a quantity of the additional paper forming material which is carried along in the interstices of the wire. An air jet 83 is positioned opposite the backing roll 16 and is arranged to blow a quantity of the additional paper forming material from the auxiliary wire directly onto the paper web. As indicated, the application of this additional material is preferably made to the wire side of the web. Backing roll 16 prevents displacement or breakage of the web by the air stream.

The web then passes through the press rolls 84 and 85 of a suction press, roll 85 being provided with a suction device 86. Thus the suction is applied to the side of the sheet opposite that to which the additional paper forming material was added.

Fig. 5 shows a further modified construction in which the wet web 99 is carried forwardly on an auxiliary carrying member 9|. Upon leaving the member 9| the web passes around guide rolls 92, 93 and into the nip of press rolls 94, 95. A traveling felt 96 passing around guide rolls 91, 98 provides for supporting the web as it passes through the press. The lower press roll is provided with a suction box 99.

The upper press roll 94 in this arrangement serves as a means for applying the additional paper forming material to the traveling web. A fountain roll I09 is suitably rotated in a trough IIlI containing the additional paper forming material so that it picks up a film'of such material upon its surface. A rotating brush I02 is arranged to contact the surface of roll I08, pick off the film of additional paper forming material and to carry it onto the surface of press roll 94 which it also contacts. This results in the application of the additional forming material to what at that point is the top side of the web, but which is actually the wire side of the web. Accordingly the suction supplied to roll 95 is effective upon the side of the sheet opposite that to which the additional paper forming material was added and this additional material is thereby properly incorporated into the body of the sheet.

Fig. 6 shows a further modification in which the wet web H is brought into contact with a traveling felt III. This felt passes under a suitable guide roll H2 on its lower run, and the bottom surface thereof is brought into contact with a color application roll H3 rotating in a trough H4 suitably supplied with the additional paper forming material. The roll H3 therefore picks up a film of color on its surface and supplies it to the surface of the traveling felt Ill. The felt travels around guide roll H5 and into contact with the traveling web of paper H0. In this way the additional paper forming material is supplied to the surface of the wet web.

After leaving the traveling felt, the web passes around guide rolls H6, H1 and into the nip of press rolls H8, H9. A traveling felt I20 passing around suitable guide rolls l2l, I22 provides for supporting and carrying the web through these press rolls. Press roll H9-is provided with a suitable suction box I23 so that suction can be applied to that side of the sheet opposite that to which the additional paper forming material was added.

It will be understood that each of the constructions shown in Figs. 4, 5 and 6 are adapted to be utilized in any suitable arrangement, such as that shown in Fig. 1, where the additional paper forming material is added after the web leaves the couch roll and before any further processing, or that shown in Fig. 3 where the sheet is subjected to a pressing operation before the additional paper forming material is added. It will also be understood that additional pressing operations prior to or subsequent to the application of the additional paper forming material and the application of the suction thereto, can be provided as desired.

While the method and forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to this precise method and apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. The method in the formation of a sheet of paper which comprises forming a wet web of paper, adding additional paper forming material including mineral filler to the lower side of the wet web to incorporate said material into and upon said lower side, turning the sheet over, and then applying suction to the lower side of the sheet to obtain a uniform distribution of the additional paper forming material in the web.

2. The method in the formation of a sheet of paper which comprises forming a wet web of paper on a traveling forming wire, carrying the sheet forward on a traveling felt, wet pressing the sheet while on the felt to extract moisture therefrom, bringing the sheet into contact with an auxiliary traveling wire, adding additional paper forming material to one side of said wire to be carried into incorporating contact with said web on the opposite side of said wire, and subsequently wet pressing the web with the incorporated additional paper forming material.

3. The method in the formation of a sheet of paper which comprises forming a wet web of paper on a traveling forming wire, carrying the sheet forwardly after leaving the wire on a traveling felt, wet pressing the sheet while traveling on said felt, bringing the sheet into contact with an auxiliary traveling wire, adding additional paper forming material through said auxiliary wire to the wet web, turning the sheet over, and subjecting the lower side of the turned-over sheet to a suction pressing operation to obtain a uniform distribution of the paper forming material in the web.

4. The method in the formation of a sheet of paper which comprises forming a wet web of paper on a traveling forming wire, bringing the sheet into contact with an auxiliary traveling wire, adding additional paper forming material to the web through said auxiliary wire, couching the web from said auxiliary wire with a traveling felt, carrying the felt with the paper web through a suction press, the press being arranged to apply suction to the side of the sheet opposite that to which the additional paper forming material was applied.

5. The method in the formation of a sheet of paper which comprises forming a wet web of paper on a traveling forming wire, carrying the sheet forward on an auxiliary traveling wire, adding additional paper forming material through said auxiliary wire to the Web, removing the web from said auxiliary wire and subjecting it to a suction pressing operation, the suction being applied to the side of the sheet opposite that to which the additional paper forming material was added, and thereafter subjecting the web of paper with incorporated additional forming material to a wet pressing operation.

6. Apparatus for forming a sheet of paper comprising a traveling wire, an auxiliary wire adapted to receive the wet web of paper and spaced from the forming Wire, means for supplying additional paper forming material through said auxiliary wire to the web of paper, a suction press, means for carrying the web of paper with the additional paper forming material through said suction press in such position that the suction is applied to the side of the web opposite that to which the additional paper forming material was added.

7. Apparatus for the formation of a sheet of paper comprising a traveling forming wire for the formation of a wet web of paper, an auxiliary wire adapted to receive the sheet upon leaving the forming wire, means for applying additional paper forming material through said auxiliary wire to the wet web, a traveling felt for couching the web from said auxiliary wire, a suction press, and means for directing said felt with the wet web of paper through said suction press in such a manner that the suction is applied to the side of the sheet opposite that to which the additional paper forming material was added.

8. The method in the formation of a sheet of paper which comprises forming a wet web of paper, adding additional mineral material in suspension as a paper forming filler material to the lower side of the wet web, and then applying suction to the opposite side of the sheet to withdraw water following such addition of mineral paper forming material, and thereby obtaining a substantially uniform incorporation of the filler material upon and into the body of said web.

9. In the formation of a sheet of paper of the character described which includes a secondary paper forming step for producing such paper of substantially uniform surface appearance characteristics, the method which comprises forming the wet web of paper, bringing a suspension of added mineral filler paper forming material into incorporating contact with the lower side of said wet web, and then applying suction to the opposite side of the sheet to draw said filler suspension into and upon the sheet and the suspension water through the sheet, and thereby obtaining substantially uniform incorporation of said additional mineral filler paper forming material into and upon the web with resultant uniform characteristics of surface appearance.

10. The method in the formation of a sheet of paper which comprises forming a wet web of paper upon a travelling forming wire, bringing the lower side of said formed wet web into m corporating contact with a suspension of added mineral filler paper forming material, and thereafter bringing the web with its added mineral filler paper forming material into efiective contact with a suction device efiective to apply suction to the side of the web opposite that to which the additional filler paper forming material was added by changing the direction of travel of the web to cause it effectively to contact said suction device, and thereby applying suction to obtain substantially uniform incorporation of said additional mineral filler paper formingmaterial into and upon the web with resultant uniform characteristics of surface appearance.

LEONARD R. GROWDON. 

